Published for the first time from the famous Moscow Guenzburg Manuscript 566, with a lengthy, scholarly introduction, comprehensive explanatory notes and comments, and detailed indices, by Prof. Simcha Emanuel. More than twenty years have passed since the first appearance of this important newly discovered Geonic compilation and as the years passed the interest in and the appreciation of this masterpiece increased greatly. We have now before us not only a new imprint, but also a newly updated edition with hundreds of corrections and supplements. Jerusalem 5779 54, 350 pp.